基于离子束辅助激光的硬质合金表面微织构制备方法研究

Study on Fabrication Method of Micro-textures on Cemented Carbide Surface Based on Ion Beam Etching-assisted Laser

目的解决纳秒激光所制备的硬质合金表面微织构尺寸不可控且质量较差的问题。方法提出了离子束刻蚀与纳秒激光复合加工技术。首次采用离子束辅助激光加工在WC/Co硬质合金表面制备凹坑型微织构,研究了激光扫描速度、重复频率、脉冲宽度和刻蚀时间4种不同加工参数对微凹坑表面形貌及结构尺寸的影响,并初步预测和建立了复合加工过程中微凹坑轮廓演变模型。结果凹坑型微织构边缘熔融物堆积量随激光重复频率的增加而增加,与扫描速度和脉冲宽度成反比,其中激光重复频率的影响最大。制备的微凹坑直径和深度可以通过改变激光重复频率和刻蚀时间来调节,使用纳秒激光以20、25、30、35 kHz重复频率加工的微凹坑经离子束刻蚀150 min后,边缘的不规则凸起高度分别由1.112、1.675、2.951、3.235μm降低至0.222、0.689、0.976、1.364μm,且刻蚀速率与激光重复频率成正比。离子束刻蚀150 min后,抛光硬质合金表面粗糙度由0.022μm增加至0.079μm,而激光织构化硬质合金表面粗糙度随刻蚀时间的增加均有所降低。结论建立了基于离子束辅助激光的表面微织构轮廓演变模型,实现了硬质合金表面微织构的高质量可控制备。

To solve the problem of uncontrollable size and poor quality of micro-textures on the surface of cemented carbide fabricated by nanosecond laser,the composite processing technology of ion beam etching(IBE)and nanosecond laser was put forward.For the first time,we propose an IBE-assisted laser processing approach to fabricate pit-type micro-textures on the surface of WC/Co cemented carbide substrate.The effects of laser scanning speed,repetition frequency,pulse width,and etching time on the surface morphology and structure size of micro-pits were studied,and the evolution model of micro-pits profile in this composite process was preliminarily predicted and established.The accumulation of molten materials at the edge of pit-type micro-textures increased with the increase of laser repetition frequency,which was inversely proportional to laser scanning speed and pulse width,and laser repetition frequency had the greatest influence among them.Besides,the diameter and depth of micro-pits fabricated can be adjusted by changing laser repetition frequency and etching time.After IBE for 150 min,the height of irregular bulge at the edge of micro-pits fabricated by nanosecond laser at 20 kHz,25 kHz,30 kHz,and 35 kHz repetition frequency decreased from 1.112μm,1.675μm,2.951μm,and 3.235μm to 0.222μm,0.689μm,0.976μm,and 1.364μm respectively,and the etching rate was proportional to laser repetition frequency.What’s more,the surface roughness of polished cemented carbide increased from 0.022μm to 0.079μm after IBE for 150 min,while which of laser textured cemented carbide decreased with the increase of etching time.In conclusion,the evolution of surface micro-textures profile based on IBE-assisted nanosecond laser is established,and the high precision controllable fabrication of micro-textures on WC/Co cemented carbide surface is realized.